title: STAT3 activation in response to IL-6 is prolonged by the binding of IL-6 receptor to EGF receptor.
abstract: The activation of STAT3 by tyrosine phosphorylation, essential for normal development and for a normal inflammatory response to invading pathogens, is kept in check by negative regulators. Abnormal constitutive activation of STAT3, which contributes to the pathology of cancer and to chronic inflammatory diseases such as rheumatoid arthritis, occurs when negative regulation is not fully effective. SOCS3, the major negative regulator of STAT3, is induced by tyrosine-phosphorylated STAT3 and terminates STAT3 phosphorylation about 2 h after initial exposure of cells to members of the IL-6 family of cytokines by binding cooperatively to the common receptor subunit gp130 and JAKs 1 and 2. We show here that when the epidermal growth factor receptor (EGFR) is present and active, STAT3 is rephosphorylated about 4 h after exposure of cells to IL-6 or oncostatin M and remains active for many hours. Newly synthesized IL-6 drives association of the IL-6 receptor and gp130 with EGFR, leading to EGFR-dependent rephosphorylation of STAT3, which is not inhibited by the continued presence of SOCS3. This second wave of STAT3 activation supports sustained expression of a subset of IL-6-induced proteins, several of which play important roles in inflammation and cancer, in which both IL-6 secretion and EGFR levels are often elevated.
authors.affiliation: School of Life Sciences, Lanzhou University, Lanzhou, Gansu 730000, People's Republic of China.
authors.forename: Yuxin
authors.initials: Y
authors.lastname: Wang
authors.forename: Anette H H
authors.initials: AH
authors.lastname: van Boxel-Dezaire
authors.forename: HyeonJoo
authors.initials: H
authors.lastname: Cheon
authors.forename: Jinbo
authors.initials: J
authors.lastname: Yang
authors.forename: George R
authors.initials: GR
authors.lastname: Stark
mesh_terms: D000970:Antineoplastic Agents / Q000378:metabolism / Q000494:pharmacology; D050822:Cytokine Receptor gp130 / Q000235:genetics / Q000378:metabolism*; D066246:ErbB Receptors / Q000235:genetics / Q000378:metabolism*; D005786:Gene Expression Regulation / Q000187:drug effects / Q000502:physiology*; D056945:Hep G2 Cells; D006801:Humans; D007249:Inflammation / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D015850:Interleukin-6 / Q000096:biosynthesis* / Q000235:genetics / Q000494:pharmacology; D053613:Janus Kinase 1 / Q000235:genetics / Q000378:metabolism; D053614:Janus Kinase 2 / Q000235:genetics / Q000378:metabolism; D009369:Neoplasms / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D053683:Oncostatin M / Q000378:metabolism / Q000494:pharmacology; D010766:Phosphorylation / Q000187:drug effects / Q000502:physiology; D011485:Protein Binding / Q000502:physiology; D050796:STAT3 Transcription Factor / Q000235:genetics / Q000378:metabolism*; D000071223:Suppressor of Cytokine Signaling 3 Protein; D050826:Suppressor of Cytokine Signaling Proteins / Q000235:genetics / Q000378:metabolism
chemical_list: D000970:Antineoplastic Agents; C508600:IL6 protein, human; C494199:IL6ST protein, human; D015850:Interleukin-6; C106644:SOCS3 protein, human; D050796:STAT3 Transcription Factor; C494086:STAT3 protein, human; D000071223:Suppressor of Cytokine Signaling 3 Protein; D050826:Suppressor of Cytokine Signaling Proteins; D053683:Oncostatin M; D050822:Cytokine Receptor gp130; C512478:EGFR protein, human; D066246:ErbB Receptors; C507904:JAK1 protein, human; C507924:JAK2 protein, human; D053613:Janus Kinase 1; D053614:Janus Kinase 2